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A bullet headed Precision, with no figure in it

TFA 45.2043.51

A German-made analog thermo-hygrometer with a synthetic-hair hygrometer and marked comfort zones.

TFA Dostmann analog thermo-hygrometer, slim upright case with twin dials

TFA 45.2043.51

A German-made analog thermo-hygrometer with a synthetic-hair hygrometer and marked comfort zones.

Type
Analog — no batteries
Hygrometer element
Synthetic-hair precision hygrometer
Origin
Entirely manufactured in Germany
Comfort zones
Marked: dry, ideal, wet
Mounting
Wall mounted or freestanding
Use
Indoor only — house, basement or garage
Temperature accuracy
Not stated by the maker
Humidity accuracy
Not stated by the maker
Range
Not stated by the maker
Amazon reference
B01KLSUYLK
EAN
4009816029379
  • The only instrument on this shelf whose sensing element is named: a synthetic-hair hygrometer, which lengthens with humidity and needs no power
  • Made entirely in Germany, stated, which no other listing on this shelf claims for any country
  • A bullet headed "Precision" that gives no figure — and five of the nine devices on this shelf are in the same position

Best for: A room where an instrument should last decades without a battery and look like an instrument

≈ $40
Check price on Amazon

Specifications

Type
Analog — no batteries
Hygrometer element
Synthetic-hair precision hygrometer
Origin
Entirely manufactured in Germany
Comfort zones
Marked: dry, ideal, wet
Mounting
Wall mounted or freestanding
Use
Indoor only — house, basement or garage
Temperature accuracy
Not stated by the maker
Humidity accuracy
Not stated by the maker
Range
Not stated by the maker
Amazon reference
B01KLSUYLK
EAN
4009816029379

What the maker puts in writing

  • Analog, no batteries
  • Synthetic-hair precision hygrometer
  • Entirely manufactured in Germany
  • Marked comfort zones: dry, ideal, wet
  • Wall mounted or freestanding, indoor only

The only named sensing element on the shelf

thanks to the synthetic-hair precision hygrometer the measurements are really precise.

Eight other listings here say “sensor” or say nothing. This one names the mechanism, and the mechanism is a hair that gets longer when the air gets damp.

That is a real thing, it works, and it has been working since the eighteenth century. It also drifts, and nothing in this listing mentions recalibrating it.

The missing number

A bullet headed “Precision” with no figure in it, at forty dollars, on a shelf where a seven-dollar digital unit publishes ±1 °F and ±5% RH.

That is the whole case against this instrument, and it is the maker’s own doing.

Availability

Read on the day this page was built: $40 at the American Amazon shop.

Read from Keepa on the day this page was last revised; stock and price both move without notice.

Prices quoted in this text were read on 2026-10-04. The live price is at the top of the page.

The questions that keep coming up

What is a synthetic-hair hygrometer?

A strand that lengthens as it absorbs moisture and drives a needle. It is the oldest working principle in the category, it needs no power, and it is the only sensing element named anywhere on this shelf. Its drawback is drift, which is why analog hygrometers are usually recalibrated — and this listing does not mention calibration.

How precise is "really precise"?

The listing does not say. The analog LittleGood on this shelf, at a third of the price, publishes ±3.6 °F and ±5% RH and includes a calibration screw. On published information, that is the better-documented analog.

Why pay for German manufacture?

It is the only origin claim on this shelf, and for a mechanical instrument with no electronics the build is most of the product. What it does not substitute for is a published tolerance.

More thermo-hygrometers

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    SwitchBot's standalone indoor thermo-hygrometer, pairing over Bluetooth to log temperature and humidity history in the SwitchBot app, alongside dew point and VPD readouts. Confirmed with a live offer on Amazon.de; we found the same listing on Amazon.fr but did not confirm a live offer there at the time of checking.

    Measures
    Indoor temperature, relative humidity, dew point, VPD
    Connectivity
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    Power
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    EAN
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    • App logging adds a history graph the basic TFA instrument in this family doesn't offer
    • We found a matching listing on Amazon.fr but did not confirm a live offer there at the time of checking

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    Measures
    Indoor temperature and relative humidity
    Mechanism
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    Display
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    EAN
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    • No battery to replace, ever — a genuine advantage over both digital instruments in this family
    • Confirmed with a live offer and a well-established listing (7+ sellers) on Amazon.de
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    Best for: Anyone who wants a permanent, no-maintenance reading on a wall or shelf and doesn't need an alarm, app, or data history.

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  • TFA Dostmann Comfort Control 30.5011 digital thermo-hygrometer

    TFA Dostmann Comfort Control 30.5011

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    Measures
    Indoor temperature and relative humidity
    Display
    Digital, with a stated mold-risk alarm and comfort-zone indicator
    Power
    Battery-powered, per the listing
    Amazon reference
    B000JG2RAG (identical ASIN on DE/FR/IT)
    • A well-established listing with double-digit seller counts on every market we checked, unlike several single-offer accessories on this site
    • The stated mold-risk alarm is a genuinely useful trigger for the humidity ranges this site's guides discuss
    • No confirmed listing found on Amazon.es at the time of checking

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Elsewhere in the spares drawer

  • DAODEFUL third-party replacement filter for the Xiaomi Smart Air Purifier 4 Compact

    DAODEFUL Replacement Filter for Xiaomi Smart Air Purifier 4 Compact

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    Filter type
    HEPA replacement filter, per the listing
    Compatible model
    Xiaomi Smart Air Purifier 4 Compact
    Source
    Third-party (DAODEFUL), not an official Xiaomi part
    Amazon reference
    B0H3DGGMLV (DE, third-party offer)
    • Built specifically for the Air Purifier 4 Compact rather than sold as a universal fit
    • A confirmed, live third-party offer on Amazon.de at the time of checking
    • Third-party, not a Xiaomi-branded part — no manufacturer warranty coverage on the filter itself

    Best for: Owners of the Xiaomi Air Purifier 4 Compact who are comfortable with a third-party filter and can order from a German-shipping listing.

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    Type
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    Size
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    Rating
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    Quantity
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    Fits
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    Construction
    Pleated, for increased surface area
    Captures
    Pet dander, pollen, mold spores and dust mites, as stated by the maker
    Replacement interval
    Not stated by the maker
    Washable
    No — these are replacement filters
    Amazon reference
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    EAN
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    • Publishes the exact size and the original part number it replaces — 14 × 17.5 × 2 in, 50070171-002 — so the fit can be verified
    • It fits two named Honeywell models and nothing else: it is not a universal filter

    Best for: A Honeywell DR90 or DR120 dehumidifier whose filter is due

    ≈ $60
    Check price on Amazon
  • Brennenstuhl Comfort-Line digital weekly timer plug

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    Programming
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    Connectivity
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All thermo-hygrometers